This invention relates to a modified ethylene-xcex1-olefin copolymer obtained by modifying ethylene-xcex1-olefin copolymer with a (meth)acryloyl group, more particularly to a modified ethylene-xcex1-olefin copolymer improved in crosslinking efficiency by introducing a specific functional group ((meth)acryloyl group). Further, this invention relates to a crosslinkable modified ethylene-xcex1-olefin copolymer rubber composition which comprises the above modified ethylene-xcex1-olefin copolymer and has excellent processability, mechanical strength, and abrasion resistance, and is excellent as a rubber material used in automobile components, machinery components, electronic components, materials for civil engineering and construction, fuel cell packing and the like.
Furthermore, this invention relates to a liquid curable rubber composition using the above modified ethylene-xcex1-olefin copolymer improved in closslinking efficiency by introducing a specific functional group xe2x80x9c(meth)acryloyl groupxe2x80x9d. Particularly, it is related to a liquid curable rubber composition including a reactive diluent and if required, a photopolymerization initiator, which composition is able to be cured by light or electron beam, and molded body thereof. They are excellent in rubber-elasticity properties such as processability of casting properties, mechanical strength and compression set property, and preferably used for rubber materials such as automobile components, mechanical components, electronic components, batteries, fuel cells, capacitors, ultracapacitors, packing materials for civil engineering and construction, gaskets, sealing materials, semiconductor sealants, mounting materials, liquid crystal display materials and various negative photo-resists.
Ethylene-xcex1-olefin copolymer and ethylene-xcex1-olefin-unconjugated polyene copolymer (hereinafter referred as xe2x80x9cethylene-xcex1-olefin copolymerxe2x80x9d) have excellent properties in heat resistance and weather resistance and the like, and are used in a wide variety of fields.
However, compared with diene rubbers such as natural rubber, styrene-butadiene rubber, isoprene rubber, butadiene rubber, nitrile rubber and the like, conventional ethylene-xcex1-olefin copolymer has a slower crosslinking rate and it is difficult to produce crosslinked rubber therefrom efficiently.
It is possible to increase the crosslinking rate of ethylene-xcex1-olefin copolymer by adding a large amount of crosslinking agent. However, if a large amount of crosslinking agent is used for crosslinking, blooming of the crosslinking agent tends to occur on the resulting crosslinked rubber surface, which is not favorable from a viewpoint of hygienic conditions.
Also, it is known in JP-A-2-51512 and JP-A-6-128427 that use of an unconjugated polyene typified by 7-methyl-1,6-octadiene increases crosslinking rate, but resulting crosslinking rate is not sufficient.
On the other hand, concerning the production of modified olefin copolymer, it is known of a method of graft reaction of maleic anhydride and the like within an extruder; a method of chemical modification of the unsaturated bond in the side-chain of the copolymer introduced by copolymerization; a method of copolymerization by radical polymerization under high temperature/high pressure; and a method of copolymerization of a functional group containing monomer with an olefin by masking specific functional group.
Using these modified olefin copolymers, a method of substitution of a hydrolyzable group bound to a silicon atom by using unsaturated alcohol such as allyl alcohol after copolymerization of ethylene, a mono-olefin having 3 to 20 carbon atoms and ethylene organosilane is known as a producing method of olefin copolymers having an unsaturated group as a side-chain introduced by chemical reaction (see JP-B-58-38443). Besides, JP-A-62-121715 discloses a modified olefin copolymer produced by grafting carboxylate compound to olefin copolymer and reacting the grafted olefin copolymer with monovalent unsaturated amine and/or unsaturated alcohol. However, there are no descriptions of (meth)acryloyl group modification.
Further, in relation to polyolefins having (meth)acryloyl group, terminally modified polyolefins are known (see JP-B-3164632). However, these polyolefins only have (meth)acryloyl group at their termini, thus olefin copolymers having (meth)acryloyl group as a random side-chain are not known. Furthermore, there are no descriptions whatsoever concerning improvement in a crosslinking rate of modified olefin copolymers having (meth)acryloyl group.
It is an object of the present invention is to provide a crosslinkable modified ethylene-xcex1-olefin copolymer and its rubber composition which has excellent processability, mechanical strength, and abrasion resistance, and is excellent as a rubber material used in automobile components, machinery components, electronic components, materials for civil engineering and construction, fuel cell packing and the like.
Another object of the present invention is to provide a liquid curable rubber composition and its molded body, using modified ethylene-xcex1-olefin copolymer wherein the rubber composition is able to be cured by light or electron beam, by introducing a specific functional group as a side-chain of the copolymer, in order to enhance processability such as casting properties, rubber elasticity such as mechanical strength and compression set property and the like; and is excellent for use of automobile components, machinery components, electronic components, batteries, fuel cells, capacitors, ultracapacitors, packing materials for civil engineering and construction, gaskets, rubber materials such as sealing materials, semiconductor sealants, mounting materials, liquid crystal display materials, and various negative photo-resists.
According to the invention, provided is, (A) (meth)acryloyl group-modified ethylene-xcex1-olefin copolymer having a (meth)acryloyl group as a side-chain thereof, and the intrinsic viscosity [xcex7] of the (meth)acryloyl group-modified ethylene-xcex1-olefin copolymer is in the range of 0.01 to 10 dl/g measured in decalin at a temperature of 135xc2x0 C. (hereinafter, may referred as xe2x80x9c(A) (meth)acryloyl group-modified ethylene-xcex1-olefin copolymerxe2x80x9d).
It is preferable that (A) (meth)acryloyl group-modified ethylene-xcex1-olefin copolymer of the invention comprises (meth)acryloyl group in an amount of 0.1 to 500 mmol per 100 g of the (meth)acryloyl group-modified ethylene-xcex1-olefin copolymer.
Also, (A) (meth)acryloyl group-modified ethylene-xcex1-olefin copolymer of the invention is provided by reacting a functional group-containing ethylene-xcex1-olefin copolymer which has at least one functional group selected from the group consisting of silyl group, hydroxyl group, alkoxyl group, amino group, carboxyl group, ester group, epoxy group, amide group, sulfone group, imido group, isocyanate group, vinyl group, vinylene group and acid anhydride group, with a (meth)acryloyl group-containing compound.
Examples of the above-mentioned (meth)acryloyl group-containing compound are represented by the following general formula (1): 
(wherein R1 represents hydrogen atom or methyl group; xe2x80x9cAxe2x80x9d represents a hydrocarbon group having 1 to 20 carbon atoms which may comprise a hetero-atom, or xe2x80x9cAxe2x80x9d represents a single bond; X1 represents silyl group, hydroxyl group, amino group, carboxyl group, epoxy group, amide group, sulfone group, imido group, isocyanate group, mercapto group, or a halogen atom; and xe2x80x9cqxe2x80x9d is an integer of 1 to 3.)
As for an example of the functional group-containing ethylene-xcex1-olefin copolymer, it may be a copolymer obtained by copolymerizing a compound represented by the following general formula (2), ethylene, an xcex1-olefin having 3 to 10 carbon atoms, and if necessary, an unconjugated polyene. 
(wherein R4 represents hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms; each of Y2, Y3 and Y4, independently represents hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a functional group selected from the group consisting of silyl group, hydroxyl group, alkoxyl group, amino group, carboxyl group or amide group, wherein at least one of Y2, Y3 and Y4 is a functional group, wherein if two or more of Y2, Y3 and Y4 are functional groups, the two or more may be an acid anhydride group (xe2x80x94(CO)xe2x80x94Oxe2x80x94(CO)xe2x80x94) or imido group (xe2x80x94COxe2x80x94NHxe2x80x94COxe2x80x94) formed by bonding to each other; xe2x80x9coxe2x80x9d is an integer of 0 to 2; and xe2x80x9cpxe2x80x9d is an integer of 0 to 5.)
At least one of Y2, Y3 and Y4 of the compound represented by general formula (2) is preferably a functional group represented by xe2x80x94SiR3mZ3-m, wherein R3 represents hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may comprise a hetero-atom, xe2x80x9cZxe2x80x9d represents a halogen atom selected from the group consisting of chlorine atom, bromine atom and iodine atom, and xe2x80x9cmxe2x80x9d is an integer of 0 to 2.
Further, as for an example of the functional group-containing ethylene-xcex1-olefin copolymer, it may be a copolymer provided by copolymerizing a compound represented by the following general formula (3), ethylene, an xcex1-olefin having 3 to 10 carbon atoms, and if necessary, an unconjugated polyene.
CH2xe2x95x90CHxe2x80x94(CH2)nxe2x80x94Yn1xe2x80x83xe2x80x83(3) 
(wherein Y1 represents a functional group selected from the group consisting of silyl group, hydroxyl group, alkoxyl group, amino group, carboxyl group or amide group; and xe2x80x9cnxe2x80x9d is an integer of 0 to 6.)
Here, Y1 of the compound represented by general formula (3) is preferably a functional group represented by xe2x80x94SiR3mZ3-m, wherein R3 represents hydrogen atom, or a hydrocarbon group having 1 to 20 carbon atoms which may comprise a hetero-atom, xe2x80x9cZxe2x80x9d represents a halogen atom selected from the group consisting of chlorine atom, bromine atom and iodine atom and xe2x80x9cmxe2x80x9d is an integer of 0 to 2.
(A) (meth)acryloyl group-modified ethylene-xcex1-olefin copolymer of the invention is preferably obtained by reacting a functional group-containing ethylene-xcex1-olefin copolymer having an intrinsic viscosity [xcex7] in the range of 0.01 to 10 dl/g measured in decalin at a temperature of 135xc2x0 C., and comprising 0.01 to 30 mol % of a structural unit (a-1) derived from a compound represented by said general formula (2), 5 to 90 mol % of a structural unit (a-2) derived from ethylene, 5 to 60 mol % of a structural unit (a-3) derived from an xcex1-olefin having 3 to 10 carbon atoms and 0 to 12 mol % of a structural unit (a-4) derived from an unconjugated polyene compound; with the compound represented by the above-mentioned general formula (1).
Also, (A) (meth)acryloyl group-modified ethylene-xcex1-olefin copolymer of the invention is preferably obtained by reacting a functional group-containing ethylene-xcex1-olefin copolymer which having an intrinsic viscosity [xcex7] in the range of 0.01 to 10 dl/g measured in decalin at a temperature of 135xc2x0 C., and comprising 0.01 to 30 mol % of a structural unit (a-1) derived from a compound represented by said general formula (3), 5 to 90 mol % of a structural unit (a-2) derived from ethylene, 5 to 60 mol % of a structural unit (a-3) derived from an xcex1-olefin having 3 to 10 carbon atoms and 0 to 12 mol % of a structural unit (a-4) derived from an unconjugated polyene compound; with the compound represented by the above-mentioned general formula (1).
Next, this invention relates to a (meth)acryloyl group-modified ethylene-xcex1-olefin copolymer-containing rubber composition (hereinafter may referred as xe2x80x9crubber composition of the inventionxe2x80x9d) characterized in comprising;
(A) above-mentioned (meth)acryloyl group-modified ethylene-xcex1-olefin copolymer, and
(B) vulcanizing agent and/or a crosslinking agent.
The rubber composition of the invention may further comprise (C) olefin copolymer rubber, other than component (A).
The invention relates to a liquid curable rubber composition (hereinafter may referred as xe2x80x9cliquid curable rubber compositionxe2x80x9d), characterized in comprising;
(A) above-mentioned (meth)acryloyl group-modified ethylene-xcex1-olefin copolymer,
(D) reactive diluent, and if necessary,
(E) a photopolymerization initiator.
It is preferably that the weight average molecular weight (Mw) of the above-mentioned component (A) comprised in the liquid curable rubber composition is in the range of 500 to 200,000 measured by gel permeation chromatography (GPC) in o-dichlorobenzene at a temperature of 135xc2x0 C.
As for the weight ratio of the above-mentioned components (A), (D) and (E), the weight ratio of component (E) is in a range of 0.01 to 10 parts based on total (100 parts) of component (A) and component (D), wherein the weight ratio of component (A) is 20 to 100 parts and the weight ratio of component (D) is 80 to 0 part.
Next, the present invention relates to a molded body which is formed by subjecting the above-mentioned liquid curable rubber composition to a light curing process or an electron-beam curing process.